bluewave

Even in a much warmer Arctic, record low pressures are still going to cause a slow down in the rate of loss. Extent losses have been below average for this time of year. So this has allowed the extent to pull back to the 2011-2020 mean for late July. Should we continue to track along this 2010s dashed line, it would mean a September daily minimum extent in the mid 4s range. NSIDC September 10 year mean September daily minimum extents 2011-2020…..4.423 million sq km 2001-2010…..5.388 1991-2000…..6.499 1979-1990…...6.959

Looks like Islip tied the record low of 55°. FOK made it down to 47° Which is a tie of its record low. 31 Jul 5:56 am 55 49 31 Jul 5:53 am 47

The record ridge and drought allowed Boise to surpass their previous warmest June and July by nearly 3°. Time Series Summary for Boise Area, ID (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jul 31 Missing Count 1 2021-07-31 79.7 2 2 2007-07-31 76.9 0 3 2015-07-31 76.3 0

Concord, New Hampshire and Tucson, Arizona are an unlikely pair to have the wettest July at the same time. Several stations in the Northeast had their wettest July on record.The Port Washington Cocorahs station had nearly 15 inches. Time Series Summary for Concord Area, NH (ThreadEx) - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 2021 13.04 2 2 1915 10.29 0 3 1897 8.56 0 4 1887 7.84 0 5 1872 7.72 0 Time Series Summary for Tucson Area, AZ (ThreadEx) - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 2021 7.39 2 2 2017 6.80 0 3 1921 6.24 0 4 1981 6.17 0 5 1919 5.53 0 NY-NS-27 Port Washington 0.8 N Lat: 40.839167 Lon: -73.68025 * indicates Multi-Day Accumulation Report Station NY-NS-27 Date Precip in. 07/01/2021 1.04 07/02/2021 1.12 07/03/2021 2.26 07/04/2021 0.79 07/05/2021 0.00 07/06/2021 0.00 07/07/2021 0.43 07/08/2021 0.01 07/09/2021 3.07 07/10/2021 2.06 07/11/2021 0.02 07/12/2021 0.21 07/13/2021 0.04 07/14/2021 0.02 07/15/2021 T 07/16/2021 0.00 07/17/2021 0.00 07/18/2021 0.28 07/19/2021 0.05 07/20/2021 0.01 07/21/2021 T 07/22/2021 0.34 07/23/2021 0.01 07/24/2021 0.00 07/25/2021 0.22 07/26/2021 2.33 07/27/2021 0.01 07/28/2021 0.31 07/29/2021 0.01 07/30/2021 0.12 Totals : 14.76 in.

Such an anomalous ridge centered near Montana for June and July doesn’t really match any ENSO composites for this time of year. It was the strongest June and July ridge that I could find for that area. 2006 and 2007 had the previous strongest ridge. But you can see this year has a more impressive 500mb anomaly.

That was just a temporary bridge put in place after the original bridge got washed away. https://www.yahoo.com/entertainment/suspension-bridge-collapses-flooded-russian-051203234.html The bridge, mainly made out of wood, was located in Uryum village, over 4,500 kilometres away from Moscow.As the truck reached the middle of the bridge, it started failing under the load, eventually falling into the swollen river along with the vehicle.The driver was later reported to have survived, but the truck could not be recovered from the water.The suspension bridge was constructed in place of a road bridge that was destroyed during one of the previous floods in the area. Currently, the residents of Uryum village do not have a way to cross the river after the accident.Bridge in Uryum is not the only one in the region that got damaged by extreme rainfall. Flooding has also damaged a bridge on Russia's Trans-Siberian railway, suspending traffic in the area.A also bridge gave way in Zabaikalsk region, some 300 km (190 miles) north of the border with China and Mongolia, The emergencies ministry said that no casualties were reported.TASS news agency said around 650 houses were reported flooded and five road bridges washed away in the flooding in the Zabaikalsk region on Thursday after heavy rain.

EPS has a cooler first week of August with the front stalling near the East Coast. Then the WAR builds during the second week of August with warmer temperatures. So maybe that’s when we’ll have a shot at our next heatwave. Aug 2-9 Aug 9-16

Models continuing with one of the strongest +PNA rises that we have seen in August. Looks like the GEFS mean gets to the +2.5 to +3.0 range. The record set in August 2009 was 3.1. So this is a continuation of the record ridging that we have seen this summer over Western North America. As the WAR begins to push back against the Eastern Trough, there may be a stalled frontal zone in the East which will be the focus of convection. Probably need a few more days to iron out the daily storm details. But it will be a high dew point and PWAT regime where the front stalls out.

Every warm up since late May has been followed by a cool down and heavy rain. So the pattern is continuing. After the highest temperatures peaked in late June, the warm ups haven’t been as intense. Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Max Temperature Departure Precipitation 2021-05-20 76 2.4 0.00 2021-05-21 83 9.1 0.00 2021-05-22 96 21.8 0.00 2021-05-23 94 19.6 0.00 2021-05-24 68 -6.7 0.00 2021-05-25 81 6.0 0.00 2021-05-26 94 18.7 0.09 2021-05-27 87 11.4 0.01 2021-05-28 71 -4.9 1.15 2021-05-29 52 -24.2 0.58 2021-05-30 53 -23.5 1.15 2021-05-31 76 -0.8 T 2021-06-01 80 2.9 0.00 2021-06-02 79 1.6 T 2021-06-03 77 -0.8 0.41 2021-06-04 83 4.9 0.19 2021-06-05 95 16.6 0.00 2021-06-06 97 18.2 0.00 2021-06-07 95 15.9 0.04 2021-06-08 93 13.6 2.19 2021-06-09 96 16.2 0.53 2021-06-10 85 4.9 0.00 2021-06-11 73 -7.4 T 2021-06-12 72 -8.8 T 2021-06-13 78 -3.1 T 2021-06-14 78 -3.5 0.16 2021-06-15 85 3.2 0.01 2021-06-16 81 -1.1 0.00 2021-06-17 81 -1.5 0.00 2021-06-18 88 5.2 0.00 2021-06-19 93 9.9 0.05 2021-06-20 91 7.6 0.00 2021-06-21 92 8.3 T 2021-06-22 80 -4.0 0.17 2021-06-23 80 -4.3 0.00 2021-06-24 79 -5.5 0.00 2021-06-25 83 -1.8 0.00 2021-06-26 86 1.0 0.07 2021-06-27 95 9.7 0.00 2021-06-28 99 13.5 0.00 2021-06-29 102 16.3 0.00 2021-06-30 103 17.1 0.54 2021-07-01 89 2.9 0.94 2021-07-02 81 -5.3 1.53 2021-07-03 70 -16.4 0.05 2021-07-04 84 -2.6 0.00 2021-07-05 89 2.3 0.00 2021-07-06 97 10.2 0.55 2021-07-07 97 10.1 T 2021-07-08 88 1.0 0.08 2021-07-09 91 3.9 1.60 2021-07-10 86 -1.1 T 2021-07-11 82 -5.2 T 2021-07-12 93 5.8 0.69 2021-07-13 78 -9.3 0.01 2021-07-14 93 5.7 0.07 2021-07-15 91 3.7 T 2021-07-16 96 8.7 0.00 2021-07-17 93 5.7 2.28 2021-07-18 86 -1.2 T 2021-07-19 86 -1.2 T 2021-07-20 90 2.8 0.00 2021-07-21 85 -2.1 0.05 2021-07-22 85 -2.1 0.00 2021-07-23 86 -1.0 T 2021-07-24 85 -1.9 0.00 2021-07-25 87 0.1 0.37 2021-07-26 93 6.2 0.08 2021-07-27 94 7.3 T 2021-07-28 87 0.4 0.04

The three stations Essex and Hudson are running warmer than all other stations by a wider margin than we usually see. 90° days Harrison...25 Caldwell...26 Newark..…27 SMQ..……..22 LGA…………17 JFK………….6 FRG………….8 ISP…………..3 BDR…………8

First time since 2007 that Newark had more 90° days in June than July. Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jun Jul Difference 2021 12 11 -1 2020 5 17 +12 2019 4 14 +10 2018 5 9 +4 2017 5 9 +4 2016 3 16 +13 2015 4 11 +7 2014 2 8 +6 2013 4 15 +11 2012 6 16 +10 2011 4 22 +18 2010 13 21 +8 2009 0 1 +1 2008 6 11 +5 2007 6 4 -2

The record MYI decline during and after the 2007 melt season was an important shift in the state of the Arctic. None of the more favorable summers since then have been able to bounce back above 6 million sq km for a NSIDC September daily minimum.There were two finishes below 4 million sq km and only three slightly above 5 million sq km. Most years since 2007 have finished somewhere in the 4s million sq km range. So a bit of a holding pattern lower range from 2013 to 2021. We’ll have to see when the next step down occurs. https://nsidc.org/news/newsroom/2007_seaiceminimum/20071001_pressrelease.html Arctic sea ice during the 2007 melt season plummeted to the lowest levels since satellite measurements began in 1979. The average sea ice extent for the month of September was 4.28 million square kilometers (1.65 million square miles), the lowest September on record, shattering the previous record for the month, set in 2005, by 23 percent https://nsidc.org/arcticseaicenews/2008/04/ New ice growth over winter 2007/2008 As the winter extent numbers indicate, new ice growth was strong over the winter. Nevertheless, this new ice is probably fairly thin. Thin ice is vulnerable to melting away during summer. Figures 4 and 5 indicate that relatively thin, first-year ice now covers 72% of the Arctic Basin, including the region around the North Pole; in 2007, that number was 59%. Usually, only 30% of first-year ice formed during the winter survives the summer melt season; in 2007, only 13% survived. Even if more first-year ice survives than normal, the September minimum extent this year will likely be extremely low. Why is there so much first-year ice this spring? Partly, it is because last summer’s record-breaking ice loss created extensive open-water areas in which new ice could form. Anomalous winds in winter can also flush thicker, older ice out of the Arctic, leaving the Arctic with a greater coverage of first-year ice. As noted by our colleague Ignatius Rigor of the University of Washington at Seattle, this winter saw a return of the Arctic Oscillation to its positive mode, an atmospheric pattern especially effective in flushing out thick, old ice. So what about the multi-year ice that remained after last year’s record ice loss? Jennifer Kay and colleagues at the National Center for Atmospheric Research found that last summer’s clear skies allowed for more intense melt of the multiyear ice, leaving it thinner than normal at summer’s end. For more on the Arctic’s transition towards younger ice, see an animation of changing sea ice age (scroll to Figure 4 of August 22, 2007 entry) by colleague Jim Maslanik and coauthors.

The GFS is close to the all-time +PNA record for the month of August. I believe the record was +3.160 at the beginning of August in 2009. Could lead to a stalled front scenario somewhere in the East when the WAR eventually pushes back against the trough. https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.pna.index.b500101.current.ascii 2009 8 1 3.160

15 inches is within reach at Port Washington. NY-NS-27 Port Washington 0.8 N Lat: 40.839167 Lon: -73.68025 * indicates Multi-Day Accumulation Report Station NY-NS-27 Date Precip in. 07/01/2021 1.04 07/02/2021 1.12 07/03/2021 2.26 07/04/2021 0.79 07/05/2021 0.00 07/06/2021 0.00 07/07/2021 0.43 07/08/2021 0.01 07/09/2021 3.07 07/10/2021 2.06 07/11/2021 0.02 07/12/2021 0.21 07/13/2021 0.04 07/14/2021 0.02 07/15/2021 T 07/16/2021 0.00 07/17/2021 0.00 07/18/2021 0.28 07/19/2021 0.05 07/20/2021 0.01 07/21/2021 T 07/22/2021 0.34 07/23/2021 0.01 07/24/2021 0.00 07/25/2021 0.22 07/26/2021 2.33 07/27/2021 0.01 07/28/2021 0.31 Totals : 14.63 in.

I believe this is our first two consecutive Julys with 10.00”+ at any of our major stations. Hard to know if this has happened before at the smaller PWS or coop sites. But the strong subtropical flavor continues with very wet and high dew point regimes of recent summers. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 1889 11.89 0 2 1975 11.77 0 3 2021 10.48 4 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 2020 11.22 0 2 1988 9.98 0 3 1984 8.65 0 4 2004 8.39 0 5 2021 8.30 4

Saturday looks like it will be the coolest morning.

The big story this summer is how we needed a record low pressure pattern to get back closer to the 2010s average following the near record finish last year.

Models hinting at a very cool ending to July. Be interesting to see if a spot like Newark can actually dip under 60°. The last time this happened on July 31st at Newark was 1956. KEWR GFSX MOS GUIDANCE 7/28/2021 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 WED 28| THU 29| FRI 30| SAT 31| SUN 01| MON 02| TUE 03| WED 04 CLIMO X/N 85| 69 78| 69 85| 59 82| 66 83| 65 82| 64 81| 67 85 67 86 Data for July 31 - NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Precipitation Snowfall Snow Depth 1932-07-31 83 56 T 0.0 M 1956-07-31 81 58 0.00 0.0 0 1936-07-31 79 58 0.00 0.0 0 1964-07-31 82 61 0.00 0.0 0

LGA gusting to 45 mph. 27 Jul 7:34 pm 83 58 43 NNW 25G45 10.00

All the July heat since 2010 has really raised the bar. Monthly Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jul Season Mean 79.9 79.9 2021 79.1 79.1 2020 80.8 80.8 2019 80.6 80.6 2018 78.2 78.2 2017 77.3 77.3 2016 79.9 79.9 2015 79.0 79.0 2014 77.0 77.0 2013 80.9 80.9 2012 80.8 80.8 2011 82.7 82.7 2010 82.3 82.3 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2011 82.7 0 2 1993 82.5 0 3 2010 82.3 0 4 1994 81.9 0 5 2013 80.9 0 6 2020 80.8 0 - 2012 80.8 0 - 1999 80.8 0 7 2019 80.6 0 8 1955 80.5 0 9 1988 80.4 0 10 2002 80.0 0 11 2016 79.9 0 12 1983 79.6 0 - 1966 79.6 0 13 1995 79.5 0 - 1949 79.5 0 14 2006 79.4 0 - 1987 79.4 0 15 1981 79.2 0 - 1952 79.2 0 16 2021 79.1 5 17 2015 79.0 0 18 1980 78.8 0 19 2008 78.7 0 20 1973 78.6 0 21 2005 78.3 0 - 1982 78.3 0 22 2018 78.2 0

This was one of the cooler Julys for a top 10 warmest June and July period. Monthly Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jun Jul Season 1994 77.8 81.9 79.9 2010 76.2 82.3 79.3 1993 75.8 82.5 79.2 2011 74.5 82.7 78.6 2021 76.2 79.1 77.7 2020 74.4 80.8 77.6 1999 74.2 80.8 77.5 2013 73.3 80.9 77.1 2008 75.3 78.7 77.0 1987 74.4 79.4 76.9 1981 74.6 79.2 76.9

Only the 7th time that Newark reached 90°on 27 days by the end of July. It’s also the first time on the list since 1991 that there were so few 90°days in July. So the May and June heat allowed Newark to make it 5th place by the end of July. Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Apr May Jun Jul Season 2010 1 2 13 21 37 1993 0 3 9 22 34 1987 0 4 11 14 29 1994 1 1 10 16 28 2011 0 1 4 22 27 1991 0 8 10 9 27 2021 0 4 12 11 27

The unusually strong 500 mb anomaly over Canada allowed us to escape the major heat this July that has been common since 2010. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jul Click column heading to sort ascending, click again to sort descending. Year Mean Avg Temperature Missing Count 2021 79.1 5 2020 80.8 0 2019 80.6 0 2018 78.2 0 2017 77.3 0 2016 79.9 0 2015 79.0 0 2014 77.0 0 2013 80.9 0 2012 80.8 0 2011 82.7 0 2010 82.3 0 Time Series Summary for LAGUARDIA AIRPORT, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Year Mean Avg Temperature Missing Count 2021 77.9 5 2020 82.9 0 2019 81.5 0 2018 79.8 0 2017 78.1 0 2016 81.1 0 2015 79.2 0 2014 77.0 0 2013 81.2 0 2012 80.4 0 2011 80.4 0 2010 82.8 0

So far this is the second most positive summer AO on record for the June into July period. 2016 wasn’t nearly as positive for this first half of summer interval. If the lower pressures were more aligned with the AO region, then it would be even more positive. That’s why the raw indices don’t always tell the complete story. It would be nice to have the daily AD anomaly to combine the two indices for a more complete picture. You can see the Arctic pressures were lowest in the series for the month of June just edging out 1970.